1. Field of the Invention
The present invention relates an image coding apparatus, an image coding method, an image decoding apparatus, an image decoding method, a record medium and an image transmitting method, and more specifically, to an image coding apparatus and an image coding method, an image encoding apparatus, an image decoding method, a record medium and an image transmitting method capable of producing a prediction image with a higher image quality in a high efficiency by executing less data process operation.
2. Description of the Related Art
Conventionally, various sorts of image compressing methods have been proposed. Among these conventional image compressing methods, there is one image compressing method which compresses by thinning (subsampling) pixels of an image.
However, when pixel data produced by simply thinning an image to compress the thinned image is directly coded, the total amount of data to be processed becomes huge. Therefore, because of the huge processing requirements, prediction images having a high image quality could not effectively be obtained effectively. Accordingly, it would be desirable to obtain a high efficiency prediction image with a higher image quality utilizing a small amount of data.
It is an object of the present invention to efficiently code image data.
It is a feature of the present invention to provide high image quality utilizing a small amount of data.
It is an advantage of the present invention to reduce the amount of transmitted or recorded data necessary to provide high quality images.
In accordance with an aspect of the present invention an apparatus for coding image data having a plurality of pixels includes means for reducing a number of pixels of original image data to generate compressed data, means for limiting a level of pixels of the compressed data to generate limited compressed data, means for correcting the limited compressed data to generate corrected data, means for predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, means for calculating, with respect to the original image data, a predictive error of the predicted data, means for determining suitability of the corrected data as coded data based upon the predicted error and means for outputting the corrected data as coded data of the original image data based upon the determined suitability.
According to another aspect of the present invention an apparatus for decoding coded data generated by coding image data includes means for receiving the coded data, and means for decoding the coded data and generating decoded image data, wherein the coded data is generated by the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, repeating the step of correcting until the corrected data becomes an optimum corrected data, and outputting the optimum corrected data as coded data.
According to yet another aspect of the present invention a method for coding image data having a plurality of pixels includes the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data of the original image based upon the predicted error, and outputting the corrected data as coded data of the original image data based upon the determined suitability.
According to a further aspect of the present invention a method for decoding coded data generated by coding image data, includes the steps of receiving the coded data, and decoding the coded data and generating decoding image data, wherein the coded data is generated by the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, and outputting the corrected data as coded data of the original image data based upon the determined suitability.
According to yet a further aspect of the present invention an apparatus for coding image data having a plurality of pixels, includes a subsampling circuit for reducing a number of pixels of original image data to generate compressed data, a limiting circuit for limiting a level of pixels of the compressed data to generate limited compressed data, a correcting circuit for correcting the limited compressed data to generate corrected data, a predicting circuit for predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, a calculator for calculating, with respect to the original image data, a predictive error of the predicted data, a determining circuit for determining suitability of the corrected data as coded data based upon the predicted error, and an output circuit for outputting the corrected data as coded data of the original image data based upon the determined suitability.
According to an additional aspect of the present invention an apparatus for decoding coded data generated by coding image data includes a circuit for receiving the coded data, and a decoder for decoding the coded data and generating decoding image data, wherein the coded data is generated by the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, and outputting the corrected data as coded data of the original image data based upon the determined suitability.
According an aspect of the present invention a method for transmitting image data having a plurality of pixels, includes the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, outputting the corrected data as coded data of the original image data based upon the determined suitability, and transmitting the outputted corrected data.
According to a further aspect of the present invention a recording medium has an encoded digital signal recorded thereon, the recording medium being prepared by the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, outputting the corrected data as coded data of the original image data based upon the determined suitability, and recording the coded data on the recording medium.
According to an additional aspect of the present invention a method for coding data having a plurality of samples, includes the steps of reducing a number of samples of original data to generate compressed data, limiting a level of samples of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original data in accordance with the corrected data and generating predicted data having a plurality of predicted samples, calculating, with respect to the original data, a predictive error of the predicted data, determining suitability of the corrected data as coded data of the original data based upon the predicted error, and outputting the corrected data as coded data of the original data based upon the determined suitability.
According to yet another aspect of the present invention, a method for decoding coded data generated by coding data, includes the steps of receiving the coded data, and decoding the coded data and generating decoding data, wherein the coded data is generated by the steps of limiting a level of samples of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original data in accordance with the corrected data and for generating predicted data having a plurality of predicted samples, calculating, with respect to the original data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, and outputting the corrected data as coded data of the original data based upon the determined suitability.
According to a further aspect of the present invention, an apparatus for coding data having a plurality of samples includes a subsampling circuit for reducing a number of samples of original data to generate compressed data, a limiting circuit for limiting a level of samples of the compressed data to generate limited compressed data, a correcting circuit for correcting the limited compressed data to generate corrected data, a predicting circuit for predicting the original data in accordance with the corrected data and for generating predicted data having a plurality of predicted samples,a calculator for calculating, with respect to the original data, a predictive error of the predicted data, a determining circuit for determining suitability of the corrected data as coded data based upon the predicted error, and an output circuit for outputting the corrected data as coded data of the original data based upon the determined suitability.
According to yet another aspect of the present invention an apparatus for decoding coded data generated by coding data, includes a circuit for receiving the coded data, and a decoder for decoding the coded data and generating decoding data, wherein the coded data is generated by the steps of reducing a number of samples of original data to generate compressed data, correcting the compressed data to generate corrected data, predicting the original data in accordance with the corrected data and for generating predicted data having a plurality of predicted samples, calculating, with respect to the original data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, and outputting the corrected data as coded data of the original data based upon the determined suitability.
According to an aspect of the present invention, an apparatus for coding image data having a plurality of pixels includes means for extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, means for storing mapping coefficients for each class, means for reading mapping coefficients for each class, means for reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and means for producing coded data by limiting a level of pixels of the corrected data.
According to another aspect of the present invention, an apparatus for decoding coded data generated by coding image data, includes means for receiving the coded data, and means for decoding the coded data to produce decoded image data, said coded data generated by the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and producing coded data by limiting a level of pixels of the corrected data.
According to yet a further aspect of the present invention, a method for coding image data having a plurality of pixels, includes the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and producing coded data by limiting a level of pixels of the corrected data.
According to another aspect of the present invention, a method for decoding coded data generated by coding image data, includes the steps of receiving the coded data, and decoding the coded data to produce decoded image data, said coded data generated by the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and producing coded data by limiting a level of pixels of the corrected data.
According to an additional aspect of the present invention, a method for transmitting image data having a plurality of pixels, includes the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, producing coded data by limiting a level of pixels of the corrected data, and transmitting the coded data.
According to an aspect of the present invention, a method for transmitting image data having a plurality of pixels, includes the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, producing coded data by limiting a level of pixels of the corrected data, and transmitting the coded data.
According to an additional aspect of the present invention, a recording medium has an encoded digital signal recorded thereon, the recording medium being prepared by the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, producing coded data by limiting a level of pixels of the corrected data, and recording the coded data on the recording medium.
According to a further aspect of the present invention, an apparatus for coding image data having a plurality of pixels, includes a subsampling circuit for extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, a memory storing mapping coefficients for each class, a circuit for reading mapping coefficients for each class, a circuit for reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and a limiting circuit for producing coded data by limiting a level of pixels of the corrected data.
According to another aspect of the present invention, an apparatus for decoding coded data generated by coding image data, includes a circuit for receiving the coded data, and a decoder for decoding the coded data to produce decoded image data, said coded data generated by the steps of extracting a plurality of pixels of the image data and generating class information corresponding to characteristics of the extracted plurality of pixels, storing mapping coefficients for each class, reading mapping coefficients for each class, reading mapping coefficients corresponding to the class information and for producing corrected data using the image data and the read mapping coefficients, and producing coded data by limiting a level of pixels of the corrected data.
According to an additional aspect of the present invention, a method of transmitting coded image data, includes the steps of receiving the coded image data, and transmitting the coded image data, wherein the coded image data is produced by the steps of reducing a number of pixels of original image data to generate compressed data, limiting a level of pixels of the compressed data to generate limited compressed data, correcting the limited compressed data to generate corrected data, predicting the original image data in accordance with the corrected data and for generating predicted data having a plurality of predicted pixels, calculating, with respect to the original image data, a predictive error of the predicted data, determining suitability of the corrected data as coded data based upon the predicted error, and outputting the corrected data as coded data of the original image data based upon the determined suitability.
These and other objects, features, advantages and aspects of the invention will become apparent when considered with reference to the following description and the accompanying drawings.